Anticancer Drugs — MCQs

Anticancer Drugs Indian Medical PG Practice Questions and MCQs

Question 421: Which of the following drugs is used to reduce toxicity caused by radiotherapy in a patient undergoing chemoradiation?

A. Vitamin A
B. Gemcitabine
C. Amifostine (Correct Answer)
D. Actinomycin D

Explanation: **Explanation:** **Amifostine** is the correct answer because it is a specialized **cytoprotective agent** (specifically a prodrug of a free-radical scavenger) used to reduce the toxic effects of ionizing radiation and certain chemotherapeutic agents. **Mechanism of Action:** Amifostine is converted by alkaline phosphatase in normal tissues into its active thiol metabolite (**WR-1065**). This active form scavenges free radicals generated by radiotherapy and binds to reactive metabolites of cisplatin. It provides selective protection to normal cells because they have higher alkaline phosphatase activity and better vascularity compared to tumor cells, which exist in an acidic, hypoxic environment. **Analysis of Incorrect Options:** * **Vitamin A:** While antioxidants are sometimes discussed in nutrition, Vitamin A is not a standard clinical radioprotectant. In oncology, Vitamin A derivatives (Retinoids) are used for differentiation therapy (e.g., ATRA in APML). * **Gemcitabine:** This is a pyrimidine antimetabolite used as a chemotherapy drug [2]. It is actually a potent **radiosensitizer**, meaning it makes radiation *more* toxic to cells, rather than protecting them. * **Actinomycin D:** An antitumor antibiotic that inhibits RNA synthesis [3]. Like gemcitabine, it acts as a radiosensitizer and can cause "radiation recall" reactions. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Indications:** Used to reduce **xerostomia** (dry mouth) in head and neck cancer patients undergoing radiotherapy and to prevent **nephrotoxicity** associated with Cisplatin. * **Common Side Effect:** Significant **hypotension** (requires monitoring blood pressure during infusion) and nausea/vomiting. * **Other Protective Agents to Remember:** * **Mesna:** Prevents hemorrhagic cystitis (Cyclophosphamide/Ifosfamide) [1]. * **Dexrazoxane:** Prevents cardiotoxicity (Anthracyclines). * **Leucovorin:** Rescues bone marrow from Methotrexate toxicity.

Question 422: What is the drug of choice for chronic lymphatic leukemia?

A. Busulphan
B. Vincristine
C. Chlorambucil (Correct Answer)
D. Mercaptopurine

Explanation: **Explanation:** **Chlorambucil** is an alkylating agent belonging to the nitrogen mustard class. It is traditionally considered the drug of choice for **Chronic Lymphocytic Leukemia (CLL)** because it is effective, orally administered, and generally well-tolerated in the elderly population, which is the primary demographic for CLL. It works by cross-linking DNA strands, leading to the inhibition of DNA synthesis and cell death in slow-growing lymphocytes. **Analysis of Options:** * **Busulphan (Option A):** This is a methane sulfonate alkylating agent specifically used for **Chronic Myeloid Leukemia (CML)**. Its primary toxicity is pulmonary fibrosis ("Busulphan lung") and skin hyperpigmentation. * **Vincristine (Option B):** A vinca alkaloid that inhibits microtubule assembly. It is a backbone of treatment for **Acute Lymphoblastic Leukemia (ALL)** and lymphomas (as part of the CHOP regimen) but is not the primary choice for CLL. * **Mercaptopurine (Option C):** A purine antimetabolite used primarily for the maintenance therapy of **Acute Lymphoblastic Leukemia (ALL)**. **High-Yield Clinical Pearls for NEET-PG:** * **Modern Shift:** While Chlorambucil is the classic textbook answer, modern management of CLL often involves **Fludarabine** (a purine analog) or targeted therapies like **Ibrutinib** (BTK inhibitor) and **Rituximab** (anti-CD20). * **Drug of Choice Summary:** * **CML:** Imatinib (Tyrosine Kinase Inhibitor). * **Hairy Cell Leukemia:** Cladribine. * **APML (M3):** All-trans retinoic acid (ATRA) or Arsenic trioxide. * **Hodgkin’s Lymphoma:** ABVD regimen (Adriamycin, Bleomycin, Vinblastine, Dacarbazine).

Question 423: What is the drug of choice for neutropenia caused by cancer chemotherapy?

A. Vitamin B-12
B. IL-11
C. Filgrastim (Correct Answer)
D. Erythropoietin

Explanation: ### Explanation **Correct Answer: C. Filgrastim** **Mechanism and Rationale:** Filgrastim is a recombinant **Granulocyte Colony-Stimulating Factor (G-CSF)**. It acts by binding to specific receptors on myeloid progenitor cells in the bone marrow, stimulating the proliferation, differentiation, and activation of **neutrophils**. Chemotherapy-induced neutropenia is a dose-limiting toxicity that increases the risk of life-threatening infections; Filgrastim effectively shortens the duration of neutropenia and reduces the incidence of febrile neutropenia. **Analysis of Incorrect Options:** * **A. Vitamin B-12:** Used for megaloblastic anemia (pernicious anemia) and peripheral neuropathy. It does not stimulate acute granulocyte production. * **B. IL-11 (Oprelvekin):** This is a recombinant interleukin used to treat **thrombocytopenia** (low platelet count) by stimulating megakaryocytopoiesis. * **D. Erythropoietin (Epoetin alfa):** This hormone stimulates the production of red blood cells and is used to treat **anemia** associated with chronic kidney disease or chemotherapy, not neutropenia. **High-Yield Clinical Pearls for NEET-PG:** * **Sargramostim:** A recombinant **GM-CSF** (Granulocyte-Macrophage Colony-Stimulating Factor) that stimulates both neutrophils and macrophages. * **Pegfilgrastim:** A pegylated form of Filgrastim with a much longer half-life, allowing for once-per-chemotherapy-cycle dosing. * **Common Side Effect:** The most frequent side effect of G-CSF therapy is **bone pain** (due to marrow expansion). * **Timing:** G-CSF should generally not be administered within 24 hours before or after chemotherapy to avoid sensitizing rapidly dividing myeloid cells to the cytotoxic drugs.

Question 424: Methotrexate should be given with which of the following to decrease its side effects?

A. Folic acid
B. Cyanocobalamin
C. Thiamine
D. Folinic acid (Correct Answer)

Explanation: **Explanation:** **1. Why Folinic Acid is Correct:** Methotrexate (MTX) is a folate antagonist that works by inhibiting the enzyme **Dihydrofolate Reductase (DHFR)**. This inhibition prevents the conversion of dihydrofolate to **tetrahydrofolate (THF)**, the active form of folate required for DNA synthesis. **Folinic acid (Leucovorin)** is a reduced form of folate (5-formyl THF). It does not require the DHFR enzyme for activation; instead, it bypasses the metabolic block created by MTX. This process, known as **"Leucovorin Rescue,"** allows normal cells to resume DNA synthesis and mitigates dose-limiting toxicities like myelosuppression and mucositis without negating the drug's efficacy if timed correctly. **2. Why Other Options are Incorrect:** * **A. Folic acid:** While folic acid is sometimes used in low-dose MTX therapy (e.g., for Rheumatoid Arthritis), it requires DHFR to be converted into its active form. In high-dose chemotherapy, MTX completely inhibits DHFR, making folic acid ineffective at "rescuing" cells. * **B. Cyanocobalamin (Vitamin B12):** B12 is a cofactor for DNA synthesis, but it does not bypass the DHFR block. It is used to reduce the toxicity of **Pemetrexed**, not Methotrexate. * **C. Thiamine (Vitamin B1):** Thiamine is a cofactor for carbohydrate metabolism (e.g., pyruvate dehydrogenase). It has no role in the folate pathway or MTX toxicity management. **3. High-Yield Clinical Pearls for NEET-PG:** * **Glucarpidase:** An enzyme used in cases of MTX toxicity/renal failure to rapidly degrade extracellular MTX. * **Hydration & Alkalinization:** Essential during high-dose MTX to prevent **crystalluria** and acute kidney injury (MTX precipitates in acidic urine). * **Drug Interactions:** NSAIDs, Penicillins, and Probenecid decrease the renal excretion of MTX, increasing its toxicity. * **Resistance:** Most commonly occurs due to decreased uptake by cells or increased DHFR enzyme production.

Question 425: Which antineoplastic drug is associated with very high cardiac toxicity?

A. Bleomycin
B. Actinomycin–D
C. Doxorubicin (Correct Answer)
D. Mitomycin–C

Explanation: **Explanation:** **Doxorubicin** (an Anthracycline antibiotic) is the correct answer because its most notorious dose-limiting toxicity is **cardiotoxicity**. This occurs via two mechanisms: the generation of iron-dependent **free radicals** (superoxide anions) that cause oxidative stress to myocytes, and the inhibition of **Topoisomerase IIβ**, leading to mitochondrial dysfunction and cell death. * **Acute toxicity:** Presents as arrhythmias or ECG changes (transient). * **Chronic toxicity:** Leads to irreversible, dose-dependent **Dilated Cardiomyopathy** and congestive heart failure. The risk increases significantly once the cumulative dose exceeds **550 mg/m²**. **Analysis of Incorrect Options:** * **A. Bleomycin:** Primarily associated with **Pulmonary Fibrosis** (due to lack of bleomycin hydrolase in lungs) and skin hyperpigmentation. It is "heart-friendly" but "lung-toxic." * **B. Actinomycin–D (Dactinomycin):** Mainly causes significant bone marrow suppression and is used primarily in pediatric tumors (Wilms tumor, Ewing sarcoma). * **C. Mitomycin–C:** Known for causing **Hemolytic Uremic Syndrome (HUS)** and delayed bone marrow suppression. **High-Yield Clinical Pearls for NEET-PG:** 1. **Dexrazoxane:** An iron-chelating agent administered to prevent/reduce Doxorubicin-induced cardiotoxicity. 2. **Monitoring:** Periodic **ECHO or MUGA scans** are mandatory to monitor the Left Ventricular Ejection Fraction (LVEF) in patients on Anthracyclines. 3. **Liposomal Doxorubicin:** Formulated to reduce cardiac uptake and decrease toxicity.

Question 426: A 56-year-old female was prescribed trastuzumab. Which of the following statements regarding this drug is FALSE?

A. It is a chimeric antibody containing human and mouse components. (Correct Answer)
B. It is used for the treatment of HER2-positive breast carcinoma.
C. It can cause cardiac toxicity.
D. It is not effective orally.

Explanation: ### Explanation **1. Why Option A is the Correct (False) Statement:** Trastuzumab is a **humanized monoclonal antibody**, not a chimeric one. In pharmacology nomenclature, the suffix **"-zumab"** indicates a humanized antibody (approx. 95% human, 5% mouse), whereas **"-ximab"** (e.g., Rituximab) denotes a chimeric antibody (approx. 65% human, 35% mouse). This distinction is high-yield as humanized antibodies generally have lower immunogenicity. **2. Analysis of Other Options:** * **Option B (True):** Trastuzumab specifically targets the **HER2/neu (ErbB2)** receptor, a member of the epidermal growth factor receptor family. It is the gold standard for HER2-positive breast cancer and is also used in HER2-positive gastric adenocarcinoma. * **Option C (True):** The most significant adverse effect of Trastuzumab is **cardiotoxicity**, typically manifesting as a decrease in Left Ventricular Ejection Fraction (LVEF) or heart failure. Unlike anthracyclines (e.g., Doxorubicin), Trastuzumab-induced cardiotoxicity is usually **reversible** and not dose-dependent. * **Option D (True):** As a large protein (monoclonal antibody), Trastuzumab would be degraded by gastric enzymes if taken orally. Therefore, it must be administered **intravenously** or subcutaneously. **3. NEET-PG High-Yield Pearls:** * **Mechanism:** It binds to the extracellular domain IV of the HER2 receptor, inhibiting downstream proliferative signaling and inducing antibody-dependent cellular cytotoxicity (ADCC). * **Monitoring:** Baseline and periodic **Echocardiography or MUGA scans** are mandatory to monitor LVEF. * **Contraindication:** Avoid co-administration with **Anthracyclines** (like Doxorubicin) due to a synergistic increase in the risk of severe cardiotoxicity. * **Nomenclature Tip:** * *-umab*: Fully human * *-zumab*: Humani**z**ed * *-ximab*: Chi**m**eric

Question 427: What is the standard regimen used in the treatment of non-Hodgkin's Lymphoma?

A. CHOP (Correct Answer)
B. COPP
C. MOPP
D. ABVD

Explanation: **Explanation:** The standard first-line chemotherapy regimen for **Non-Hodgkin’s Lymphoma (NHL)**, particularly Diffuse Large B-Cell Lymphoma (DLBCL), is **CHOP**. In modern practice, this is often combined with Rituximab (R-CHOP). **Breakdown of CHOP:** * **C:** Cyclophosphamide (Alkylating agent) * **H:** Hydroxydaunorubicin/Doxorubicin (Antitumor antibiotic/Anthracycline) * **O:** Oncovin/Vincristine (Vinca alkaloid) * **P:** Prednisolone (Glucocorticoid) **Analysis of Incorrect Options:** * **MOPP (Mechlorethamine, Oncovin, Procarbazine, Prednisolone):** This was the historical gold standard for **Hodgkin’s Lymphoma (HL)** but has been largely replaced due to high toxicity (infertility and secondary leukemias). * **ABVD (Adriamycin, Bleomycin, Vinblastine, Dacarbazine):** This is the current **standard of care for Hodgkin’s Lymphoma**. It is preferred over MOPP because it is less gonadotoxic and less leukemogenic. * **COPP (Cyclophosphamide, Oncovin, Procarbazine, Prednisolone):** Used occasionally in HL as a substitute for MOPP, but not the standard for NHL. **High-Yield Clinical Pearls for NEET-PG:** 1. **Doxorubicin Toxicity:** Monitor for **dilated cardiomyopathy** (cumulative dose-dependent). Dexrazoxane can be used as a cardioprotectant. 2. **Vincristine Toxicity:** Look for **peripheral neuropathy** (foot drop/paresthesia) and paralytic ileus. It is "M-phase" specific and notably **bone marrow sparing**. 3. **Cyclophosphamide Toxicity:** Characterized by **hemorrhagic cystitis** due to the metabolite **Acrolein**. This is prevented by aggressive hydration and **MESNA**. 4. **Rituximab:** A monoclonal antibody against **CD20**, frequently added to CHOP for B-cell NHL.

Question 428: Imatinib is useful in the treatment of which condition?

A. Neurofibromatosis
B. CD117 positive GIST (Correct Answer)
C. Neuroendocrine tumor of pancreas
D. Breast cancer

Explanation: **Explanation:** **Imatinib** is a revolutionary targeted therapy that acts as a selective **tyrosine kinase inhibitor (TKI)**. Its primary mechanism involves inhibiting the Bcr-Abl tyrosine kinase (associated with Philadelphia chromosome), but it also potently inhibits the **c-KIT (CD117)** and **PDGFR** (Platelet-Derived Growth Factor Receptor) tyrosine kinases. 1. **Why Option B is Correct:** Gastrointestinal Stromal Tumors (GIST) are characterized by the overexpression of the **c-KIT proto-oncogene (CD117)** in approximately 95% of cases. This mutation leads to constitutive activation of tyrosine kinase, driving tumor growth. Imatinib binds to the ATP-binding site of the c-KIT receptor, blocking downstream signaling and inducing apoptosis. It is the first-line medical treatment for metastatic or unresectable CD117-positive GIST. 2. **Why Other Options are Incorrect:** * **Neurofibromatosis:** Primarily managed surgically or with MEK inhibitors (like Selumetinib) for plexiform neurofibromas. * **Neuroendocrine tumor (NET) of pancreas:** Often treated with Somatostatin analogues (Octreotide), Sunitinib (a multi-kinase inhibitor), or Everolimus (mTOR inhibitor). * **Breast cancer:** Managed with hormonal therapy (Tamoxifen), HER2 inhibitors (Trastuzumab), or traditional cytotoxic chemotherapy. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Imatinib is the DOC for **Chronic Myeloid Leukemia (CML)** in the chronic phase. * **Mechanism:** Competitive inhibition of the ATP-binding site on the tyrosine kinase enzyme. * **Side Effects:** The most characteristic side effect is **periorbital edema** (fluid retention). * **Resistance:** Often occurs due to point mutations in the kinase domain (T315I mutation), where **Ponatinib** is used as an alternative.

Question 429: Which of the following is a cardiotoxic anticancer drug?

A. Bleomycin
B. Doxorubicin (Correct Answer)
C. 5-Fluorouracil
D. Dactinomycin

Explanation: **Explanation:** **Doxorubicin** is the correct answer because it belongs to the **Anthracycline** class of antibiotics, which are notorious for their dose-dependent **cardiotoxicity** [1]. The underlying mechanism involves the generation of **superoxide free radicals** and iron-dependent lipid peroxidation, which damages the myocardial cells (which have low levels of protective catalase) [2]. This toxicity manifests in two forms: 1. **Acute:** Transient ECG changes and arrhythmias [1]. 2. **Chronic:** Cumulative dose-related **Dilated Cardiomyopathy (DCM)** and congestive heart failure [1]. **Analysis of Incorrect Options:** * **A. Bleomycin:** Primarily known for **Pulmonary Fibrosis** (interstitial pneumonitis). It lacks significant cardiac side effects but can cause skin hyperpigmentation. * **C. 5-Fluorouracil:** An antimetabolite primarily associated with GI toxicity, hand-foot syndrome, and rarely, coronary vasospasm (angina) [4], but it is not the classic "cardiotoxic" drug compared to Doxorubicin. * **D. Dactinomycin:** An antitumor antibiotic used in pediatric tumors (Wilms tumor) [3]; its dose-limiting toxicity is primarily bone marrow suppression and GI distress. **High-Yield Clinical Pearls for NEET-PG:** * **Antidote:** **Dexrazoxane** (an iron chelator) is used to prevent/reduce Doxorubicin-induced cardiotoxicity [2]. * **Monitoring:** Periodic **ECHO/MUGA scans** to monitor Left Ventricular Ejection Fraction (LVEF) are mandatory [1]. * **Cumulative Dose:** The risk of heart failure increases significantly when the cumulative dose of Doxorubicin exceeds **450–550 mg/m²** [1]. * **Liposomal Doxorubicin:** This formulation is used to reduce cardiotoxicity by altering drug distribution.

Question 430: Which of the following anticancer drugs exhibits dose-dependent least neurotoxicity?

A. Cisplatin
B. Bleomycin (Correct Answer)
C. Doxorubicin
D. Vinblastine

Explanation: **Explanation:** The correct answer is **Bleomycin**. In the context of the options provided, Bleomycin is unique because its dose-limiting toxicity is **pulmonary fibrosis**, not neurotoxicity. It has virtually no significant penetration into the central nervous system and does not typically cause peripheral neuropathy, making it the drug with the least neurotoxicity among the choices. **Why the other options are incorrect:** * **Cisplatin:** This platinum-based agent is notorious for significant **dose-dependent neurotoxicity**, primarily manifesting as peripheral sensory neuropathy (stocking-glove pattern) and ototoxicity (high-frequency hearing loss). * **Vinblastine:** As a microtubule inhibitor (Vinca alkaloid), it interferes with axonal transport. While Vinblastine is more associated with bone marrow suppression than Vincristine, it still carries a significant risk of peripheral neuropathy and autonomic dysfunction. * **Doxorubicin:** While its primary dose-limiting toxicity is **cardiotoxicity**, it can contribute to "chemo-brain" (cognitive impairment) and, in high doses or specific formulations, exhibits more neurological interference than Bleomycin. **High-Yield Clinical Pearls for NEET-PG:** 1. **Bleomycin Specifics:** It acts by inducing free radical formation, causing DNA strand breaks. It is "cell cycle specific" for the **G2 phase**. 2. **The "B" Rule:** Remember **B**leomycin for **B**low (Pulmonary Fibrosis) and **B**one marrow sparing (it is one of the few anticancer drugs that does not cause significant myelosuppression). 3. **Cisplatin Triad of Toxicity:** Nephrotoxicity (prevented by Amifostine/hydration), Ototoxicity, and Peripheral Neuropathy. 4. **Vincristine vs. Vinblastine:** Vincristine is dose-limited by **Neurotoxicity**; Vinblastine is dose-limited by **Bone marrow suppression** ("Blast" = Bone marrow).

Practice by Chapter

Principles of Cancer Chemotherapy

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Alkylating Agents

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Antimetabolites

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Antitumor Antibiotics

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Plant Alkaloids

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Topoisomerase Inhibitors

Practice Questions

Hormonal Agents

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Targeted Therapy

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Immunotherapy

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Management of Chemotherapy Side Effects

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